Retailers currently have a very high spend on running display freezers. One of the reasons that the cost of these freezers is relatively high is that in order to guarantee food safety, the units have to operate so that the warmest parts of the freezer (known as hot spots) are maintained at or below the maximum permitted temperature for food storage. Such hot spots can occur for several reasons but are mainly due to the poor air flow around the shelves and the addition/movement of items on the shelf.
The invention was devised in this context.